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An Ounce of Prevention

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'Shouldn't I have a mammogram?' Second leading cause of cancer death in US women ... Self Exam, Physician Exam, Mammogram. Treatment is available. Surgery, ... – PowerPoint PPT presentation

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Title: An Ounce of Prevention


1
An Ounce of Prevention
  • Duke Family Medicine
  • Common Problems in Primary Care

2
Opportunity knocks
  • You are starting a new job in your hometown and
    the senior partners of the group ask you to set
    up a prevention protocol for the practice.
  • A 16-year old student from the high school track
    team with a stated purpose of sports physical
    is your next patient.
  • A couple presents for a pre-marital blood test
    with state form in hand.
  • You have been asked to be on the committee for a
    local community health fair.
  • You are seeing an 11-month-old for his third ear
    infection.
  • Your first patient of the afternoon has a family
    history of breast cancer and she is starting to
    notice hot flashes and missing periods.
  • The local paper has an article about the death of
    a local teenager in a corn silo.
  • There is a new shirt factory in town and several
    of your patients are joining the work force
    there.

3
What we will cover
  • Principles of prevention
  • Primary prevention
  • Secondary
  • Screening
  • Benefits Risks of Screening
  • Sensitivity, Specificity of a test
  • Positive Predictive Value of a test
  • How prevalence effects Prediction
  • Shared decision making
  • Counseling

4
Purpose
  • Reduce incidence of disease
  • Example Immunization
  • Reduce mortality and morbidity of disease by
    early detection
  • Modifying personal behavior
  • Knowledge as power

5
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6
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7
Start at the beginning
  • Risk profile
  • Family history
  • Age
  • Gender
  • Ethnic origin
  • Exposures
  • Lifestyle
  • Targeted prevention
  • Population profile

8
Opportunity Knocks
  • Are you answering the door?

9
Family Hx
  • What 6 target adult diseases should be
    highlighted in family history?
  • Heart disease
  • Diabetes
  • Stroke
  • Breast cancer
  • Ovarian cancer
  • Colon cancer

10
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11
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12
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13
Strategies
  • Primary
  • Prevention of disease occurrence
  • Secondary
  • Screening asymptomatic population for risk
  • Preclinical
  • Tertiary
  • Treatment of symptomatic population
  • Minimize complications

14
Prevention Components
  • Screening
  • Test or standardized exam
  • Immunizations
  • Chemoprevention
  • Drugs or biologicals to prevent disease
  • Counseling

15
Does it work?
  • Stroke mortality down 50 since 1972
  • Early detection and treatment HTN
  • Cervical cancer mortality reduced by 80
  • Neonatal screening
  • Reduction in cognitive dysfunction
  • PKU
  • Congenital hypothyroidism

16
Primary Prevention
  • Immunizations

17
Chemoprophylaxis
  • ASA for adults at high risk for CAD
  • A Recommendation
  • Benefit gt risk
  • Tamoxifen or raloxifene for breast cancer
  • No in average or low risk
  • Counseling and shared decision making in high
    risk

18
Chemoprophylaxis
  • Post-exposure prophylaxis
  • H. influenza, B
  • Hepatitis A
  • Hepatitis B
  • Meningococcus
  • Rabies
  • Tetanus

19
Chemoprophylaxis
  • Hormone replacement
  • Patient preference
  • Risk gt benefit
  • Individual risk assessment
  • I recommendation
  • Travel
  • Malaria prophylaxis
  • Yellow fever

20
Screening
  • Secondary prevention

21
Criteria for effective screening
  • The burden of illness is high
  • Detection is possible before symptoms are evident
  • Treatment is available, acceptable reduces
    morbidity and mortality if applied early
  • Benefits of treatment outweigh harm including
    discomfort anxiety
  • First, do no harm

22
Recipe for success
  • Test is accessible
  • Test is acceptable to patient
  • Patient willing to participate in follow-up and
    treatment
  • Cost effective

23
Natural History of Disease
  • ? ? ?
  • 1 ? ?2 ? ?3 ?? 4
  • Biological onset
  • Early diagnosis possible
  • Usual clinical diagnosis
  • Outcome

24
Natural history of disease
  • Critical point

Biological onset
Symptomatic onset
Outcome
Screening
Case Finding
Critical point therapy effective prior to this
point in natural history of disease, ineffective
afterwards
25
Critical point and screening
  • Identify the disease/s illustrates a critical
    point suitable to screening
  • Colorectal cancer
  • Cervical cancer
  • Pancreatic cancer

26
Critical point
  • Cervical cancer
  • Critical point occurs prior to onset of symptoms
  • Effective intervention available in asymptomatic
    phase
  • Intervention improves outcome
  • Colorectal cancer
  • Pancreatic cancer
  • Aggressive
  • Short history

27
Screening bias
  • Lead-time bias
  • Length bias

28
Screening advances time of diagnosis, not
survival time
29
50 detected by screening while remainder
progress to clinical symptoms during screening
interval
False Security
Longer asymptomatic period, more likely to be
detected in screening interval
30
Screening guidelines
  • USPSTF
  • Review evidence of effectiveness for screening in
    asymptomatic, average risk population
  • Make recommendations for clinical preventive
    services
  • Identify research agenda for clinical prevention

31
Organizations
  • USPSTF
  • Evidence based
  • Specialty organizations
  • AAFP
  • ACP
  • ACPM
  • Etc.

32
USPSTF Ratings Evidence
  • Strongly recommends that clinicians provide the
    service to eligible patients. (Good evidence)
  • Provide this service to eligible patients.
    (Fair evidence)
  • No recommendation for or against routine
    provision of the service. (Fair evidence, Close
    balance)
  • Recommends against routinely providing the
    service to asymptomatic patients. (Ineffective
    or risk gt benefit)
  • Evidence is insufficient to recommend for or
    against routinely providing the service.
    (Evidence lacking or poor quality or conflicting,
    cannot determine risk benefit ratio)

33
Quality of Evidence
  • Good Evidence includes consistent results from
    well-designed, well-conducted studies in
    representative populations that directly assess
    effects on health outcomes.
  • Fair Evidence is sufficient to determine effects
    on health outcomes, but the strength of the
    evidence is limited by the number, quality, or
    consistency of the individual studies,
    generalizability to routine practice, or indirect
    nature of the evidence on health outcomes.
  • Poor Evidence is insufficient to assess the
    effects on health outcomes because of limited
    number or power of studies, important flaws in
    their design or conduct, gaps in the chain of
    evidence, or lack of information on important
    health outcomes.

34
Example Diabetes
  • USPSTF
  • Screening does detect in pre-symptomatic phase
  • No early intervention evidence (I)
  • Screening approved for hypertension and
    hyperlipidemia patients (B)
  • Modifies management
  • The Critical Point
  • ADA
  • Start age 45
  • FPG
  • In a health care setting
  • Every 3 years
  • Earlier and more frequent if BMI gt 25 with
    additional risk factors
  • E recommendation

35
How to judge a Screening Test
  • Sensitivity
  • In asymptomatic phase
  • Specificity
  • Avoid false positives
  • Positive Predictive Value (PPV)
  • When yes means yes
  • Negative Predictive Value (NPV)

36
Indices of accuracy
  • Sensitivity
  • Proportion with disease who correctly test
  • Low proportion of false-negatives
  • Specificity
  • Proportion without disease who correctly test
  • Low proportion of false-positives
  • Gold standard
  • Sensitivity and Specificity describe test
    accuracy and areindependent of disease prevalence

37
Accuracy
  • Sensitivity
  • a/ac
  • Specificity
  • d/bd
  • PPV
  • a/ab
  • NPV
  • d/cd

38
Risks
  • List potential risks of a poorly sensitive test
  • False negatives
  • List the potential risks of a poorly specific
    test
  • False positives

39
The potential for harm is real
40
Accuracy
  • Sensitivity
  • a/ac
  • Specificity
  • d/bd
  • PPV
  • a/ab
  • NPV
  • d/cd

41
Prevalence
The total number of cases of a disease in a given
population at a specific time.
42
Predictive Value
  • Given a positive results, what is the probability
    that disease is present?
  • Positive Predictive Value (PPV)
  • Proportion who test have disease
  • Dependent on disease prevalence in the population
    studied.

43
Prevalence and PPV
90 Sensitivity, 95 Specificity
44
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45
Reliability
  • Reproducible results
  • Valid
  • Reliable

46
A Clinical Question
  • A 30 y.o. woman presents to your office for a
    check-up. She has no history of illness.
  • What preventive measures would you recommend on
    the basis of age and sex alone?
  • What data do you need to decide about additional
    screening?

47
Routine recommendations
  • Alcohol Misuse
  • ASA for prevention of CVD
  • Blood pressure screening
  • BCRA mutation screening
  • Genetic risk assessment for ovarian and breast
    cancer susceptability
  • Breast cancer prevention medication
  • Cervical cancer screening
  • Alcohol B
  • ASA high risk
  • BP screening A, 18 and older
  • BCRA High risk
  • Breast Ca prevention High risk
  • Cervical cancer screening A, sexually active
    with a cervix

48
30 y/o female
  • Chlamydia screening
  • Dental and periodontal disease
  • Depression
  • Diabetes
  • Diet
  • G.C.
  • HIV
  • Chlamydia A, through age 25 and high risk
  • Dental B, dental care, flossing, fluoride, oral
    cavity exam
  • Depression B, screening in appropriate setting
  • Diabetes B, high risk HTN, Hyperlipidemia
  • Diet Hyperlipidemia or other risk factors for
    chronic disease, B
  • G.C. high risk, age lt 25
  • HIV Risk based A

49
30 y/o old female
  • Lipids
  • Obesity
  • Syphilis
  • Tobacco use
  • Lipids high risk men age 35, women 45 treat if
    high and at increase risk for CHD younger if
    risk high (20-30 men, 20-45 women)
  • Obesity B, offer intensive counseling and
    behavioral interventions.
  • Syphilis A for high risk
  • Tobacco A, screen and offer intervention
  • TB screening high risk

50
Level D
51
But, doc!
  • Shouldnt I have a mammogram?
  • Second leading cause of cancer death in US women
  • 1/8.2 women in US diagnosed over lifetime
  • 1/30 will die because of the disease
  • gt 50 without identified risk factors

52
Cases of Breast Cancer in 2000
ACS Surveillance Research, 2000
53
Breast Cancer
  • Prevalence Varies by Age
  • 20 cases/100,000 women _at_ age 30
  • 180 cases/100,000 women _at_ age 50
  • Risk Factors
  • Age, Genetic, Hormones, Radiation, Prior Cancer,
    High Fat Diet, Alcohol

54
Cumulative Risk of Breast CA
55
Mammogram _at_ age 30
Prevalence 20/100000 Sensitivity
70 Specificity 95 PPV 0.003
For every case, 358 undergo needless evaluation,
cost and anxiety 5013/14358
56
Mammogram _at_ age 60
Prevalence 180/100000 Same sensitivity and
specificity PPV 0.026
For every case, 39 get worked up needlessly
5119/128
57
What about outcomes?
58
Outcome Risk reduction
  • Relative risk and RR reduction
  • Probability of event in active group/probability
    in control group
  • RR reduction
  • Absolute risk/ probability in control group

59
Screening effectiveness
  • Gain in life expectancy
  • Cost per case detected
  • Cost per life saved
  • Gain in quality-adjusted years
  • Number needed to screen
  • How many need to be screen impact one person

60
Mammography
  • Does screening reduce disease?

61
For Breast Cancer
  • The burden of illness is high
  • Most common CA in women with 182,000 new cases
    44,000 deaths in 2000
  • Detection is possible before symptoms
  • Self Exam, Physician Exam, Mammogram
  • Treatment is available
  • Surgery, Chemotherapy, Radiation
  • Treatment value exceeds the discomfort anxiety

62
Mammography Benefit
  • Swedish study
  • 4 randomized studies
  • 247,010 women
  • 15.8 years follow-up
  • 21 reduction in mortality
  • RR 0.79 in screened group
  • Statistically significant in 55-69 y/o
  • Benefit evident at 4 years out
  • Increased to 10 years
  • 20-30 reduction in mortality realized after a
    delay of 6-10 years

63
USPSTF
  • 2002 USPSTF recommendations
  • No evidence of value for ages lt40
  • Strongest evidence age 50-69
  • Every 1-2 years beginning at age 40
  • Most studies indicate mortality benefit
  • Absolute benefit smaller in 40s due to
    incidence in the age group vs. gt50
  • No proof of value gt 70 but likely is a good idea
  • In absence of co-morbidities that reduce life
    expectancy

64
What if she were a he?
  • Alcohol Misuse
  • ASA for prevention of CVD
  • Blood pressure screening
  • Chlamydia screening
  • Dental and periodontal disease
  • Depression
  • Diabetes
  • Diet
  • G.C.
  • HIV
  • Lipids
  • Obesity
  • Syphilis
  • Tobacco use

65
He?
66
When you get older
67
Older
The younger woman was D.
68
Older
69
Older
70
Colorectal cancer
  • Long latency 10 years
  • Large Adenomatous Polyps
  • Risk assessment
  • Fecal Occult Blood Test for Colon Cancer
  • Sensitivity 26-92
  • Specificity 90-99
  • PPV 2-11
  • Sigmoidoscopy
  • 50 reduction in overall CRC mortality
  • Colonoscopy
  • Awaiting data on outcome comparison

71
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72
Shared decision making
  • Serum PSA for Prostate Cancer
  • Sensitivity and Specificity
  • Varies with cutoff value, age and comorbidity
  • PPV 20
  • 2nd leading cause of CA death in men
  • Does screening improve outcome?

73
Food for thought
74
Shared decisions
75
Shared decisions
  • Would you feel better knowing?
  • Not knowing?
  • What happens if the PSA is elevated?
  • What happens if you have cancer?
  • What difference will it make for you to know?

76
Shared decisions
77
Shared decisions pros and cons
78
Guidelines
  • USPSTF
  • Recommendation level I
  • Major medical organizations
  • Discuss potential benefits and possible harms
  • Consider patient preferences.
  • Individualize the decision to screen.
  • No endorsement of universal screening

79
Selective screening
  • Most likely to benefit
  • Age over 50
  • Younger men at high risk (45)
  • African American men
  • Younger age of onset
  • More aggressive disease
  • First-degree relative
  • Unlikely to benefit
  • Men with less than 10 year life expectancy

80
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81
Knowledge as power
  • Family history
  • CHD
  • Risk increase x 2-6
  • Cancer
  • Colon 2-5 x increase
  • Breast 2-6 x increase
  • Prostate
  • Nature vs. nurture
  • Targeted screening ?
  • Targeted intervention
  • BEHAVIOR CHANGE?

82
Motivation
  • Identify stage of change
  • Tailor made messages
  • Patient preference
  • Consider
  • Knowledge and literacy
  • Beliefs
  • Culture
  • Support
  • Reflective listening

83
Resources
  • www.myhq.com
  • ID pickens
  • Password marshall
  • USPSTF
  • The Bible of prevention
  • Asymptomatic population
  • Office based
  • Primary and secondary prevention
  • Evidence based
  • http//fmclerkship.mc.duke.edu

84
Primum non nocere
  • FINIS

85
Five Rs
  • Relevance
  • Risks
  • Rewards
  • Roadblocks
  • Repetition

86
Behavioral counseling
  • Assess
  • Advice
  • Agree
  • Assist
  • Arrange

87
Encourage self-management
  • Realistic goals
  • Education
  • Support
  • Write it down
  • Gold star treatment
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